Two-cycle engine and pump



Jan. 15, 1952 oQH. ERICKSON TWO-GYCLE ENGINE AND PUMP 5 Sheets-Sheet lFiled Jan. l2, 1948 3 Sheets-Sheet 2 v JNVENToR.

05m@ H. E E/cKso/Y /f o. H. ERICKSON TWO-CYCLE ENGINE AND PUMP QN NU,@kfw Nm. v. wm, m uw MN \l\ www Jan. 15, 1952 Filed Jehu. 12, 1948 O. HuERICKSON `Ian. l5, 1952 CYCLE ENGINE AND PUMP TWO- 3 Sheets-Sheet 5Filed Jan. '12, 1948 Patented Jan. 15, 1952 UNITED l STATES PATENTGFFICE y Two-CYCLE ENGINE AND PUMP Oscar II. Erickson, PnyallulnWash.Application January 12, 194s, serial No. 1,742

2 Claims.

This invention relates to internal combustion engines and it hasreference more particularly to internal combustion engines that operateon a two stroke cycle and wherein each power unit of the enginecomprises a power cylinder and a companion pump cylinder, the lattercontaining a reciprocating piston whereby carbureted fuel charges arecaused to lbe sucked into the cylinder and then forcibly driven into thepower cylinder in timing with the reciprocal action of a power pistonthat is contained in the power cylinder. The present invention hasreference particularly to engines of the types described and illustratedin my United States patents issued under Numbers 1,890,148 and2,294,332, and is an improvement thereon.

It is the principal object of this invention to provide an engine of theabove stated kind wherein provision is made for a better control of theiiow of gases between the cylinders through an intercommunicatingpassage which has been referred to as an exchange passage; the timing ofthe opening of the exchange passage being controlled by sleeve valvesthat operate respectively in the power and pump cylinders, and whichvalves have ports that time the admittance of fuel charges into the pumpcylinder, their advancement into vthe power cylinder, and the exhaustingof used charges from the engine.

It is also an object of this invention to provide a novel arrangement ofports in the sleeve valves for the control of the flow of gases throughthe transfer passage that permits of admittance of burned gases from thepower cylinder into the pump cylinder for a better volatilizing of fueland an increase in power therefrom.

Other objects ofthe invention reside in the advantages to be obtained,by the use of twov sleeve valves for the control of gases, over the useof a single sleeve as used in my prior patent. Still further objectsreside in the details of construction of parts and in the mode ofopera'-v tion, as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I haveprovided the improved details of construction, the preferred forms ofwhich are illustrated in the accompanying drawings, wherein- 7 1 is aside elevation of an engine embodying the improvements of the presentinvention therein; one power unit being shown in vertical section forbetter understanding.

Fig. 2 is a horizontal section taken substantially on line 2-2 in Fig.1.

Figs. 3 to 7, inclusive, are views diagrammatically illustrating themode of operation of the engine, and the changing relationship of powerand pump pistons, and the sleeve valves with the rotation of the crankshaft to which these parts are connected. l

(Cl.y 123-70) Fig. 8 is an enlarged, sectional detail showing theunchanging relationship and relative size of passages in the cylinderwalls and the relationship of ports of the valve sleeves which movereclprocally across the cylinder ports.

Referring more in detail to the drawings- I In Figs. 1 and 2, I haveillustrated, in elevation and section, an engine embodied by the presentinvention and comprising two power units; each unit including a powercylinder and a pump cylinder. It is to be understood, however, that suchan engine might comprise one or more of said units, all delivering powerto the same crank shaft. and could be made in various sizes to meetrequirements or particular uses. The engine, as`

here shown, comprises a cylinder block IIJ in which there are formed twopower cylinders I2-I2 and two pump cylinders I3-I3. The power cylindersare parallel and located at opposite ends of the block and the pumpcylinders are located between the power cylinders, parallel in linetherewith and adjacent each other.

It is shown best in Fig. 2 that the cylinder block I0 is formed at oneside with a fuel intake port I5, Ato which a manifold I6 leading from asource of carbureted fuel is connected, and from which port I5, passagesI1-II open laterally into the two pump cylinders.

It is also shown in Fig. 2 that each pump cylinder has a passage I8therefrom into its companion l power cylinder, which passages I havedesignated as the transfer passages and through which passages the fuelcharges are forcibly advanced from the pump cylinders into the powercylinders.

Each power cylinder I2 is shown in Fig. 2 as being equipped with exhaustports 20--20 at opposite sides and, as will be understood by refer-Vence to Fig. 1,the exhaust ports are at a slightly lower level than thefuel inlet port I5 of the pump cylinder, and the transfer passage I8 isat a higher level than the inlet port. The relationship of the fuelintake port, the exhaust port and the transfer passage with reference toa horizontal level in each power unit, is best under--` stood byreference to Figs. 3 to 7, wherein, for

purpose of better understanding, the intake and4 exhaust ports have beenshown as located in thev cylinder walls opposite the transfer passage.

Since all units of the engine are alikein construction and mode ofoperation, the following description which will bedirected to one unitonly will be understood to apply equally to all that may be incorporatedin an engine. Reciprocally fitted in the power cylinder I2 is a sleevevalve member 25, and likewise reciprocally fitted in the pump cylindersare sleeve valve members 26. Each sleeve valve member is of substantiallength, extending substantially the full length of its cylinder andprojecting somewhat below the cylinder block. These sleeves are as inthe usual manner for igniting the fuel charges in the cylinder, and thisheadhasadepending portion 28a extended down into .the cylinder to limitthe explosion chamber volume.

Likewise, the head 2S eXtendsdOWn'into the' pump cylinder I3 to theapproximate level Aof the transfer passage andslightly above the upperlimit of travel of the pump piston.

vReciprocally containedinfthe'sleeve25 of `the power .cylinder is thepower piston 32, and likewise reciprocally contained in the sleeve 25 isapump 'piston33.

Mounted in the central, vertical planeof the cylinders, below the block,is a crankshaft 35, revolubly mountedat its ends in suitable bearings-as at 36. This crank shaft, for Veach unit of the engine, is 'formedwith a crank throw 31 connected by a rod v38 with the wrist'pin 39 ofpower piston 32. Likewise, the crank shaft has a crank throw connectedby rod 42 with 'the wristpin 43 of pump piston 33. Between the points ofconnection with rods Y38 and 42, the crank shaft is formed with Vaneccentric-journal 44 onfwhich a connecting rod 155 is mounted, and thisrod is joined at its upper endwith the" lugs 21--21 ofthe sleeve valves25 .and 26 `by meansof a wrist pinfd'l.

The lengths of the throws-or crank'arms 31 and Vr`4I) are equal, withthe throw 4U exactly ninety degrees in advance ofthe throw 31. Theeccentric 46 is exactly 67% degrees in advance of crank arm I4U of thepump and is relatively short; the relationship of the several crank armsbeing best shown diagrammatically inFg. 7, which shows the crank arm'31*extended' horizontally to the left of the crank shaft axis, the arm110 extending vertically upwardirom the shaft center and crank arm 44extending angularly=671/2 degrees in advance of arm 40.

The sleeve valvez of each pump piston is vprovidedat one side with aport' 50 adapted, with the reciprocal action of the sleeve, vto movedownwardly 'and upwardly across the corresponding intake port I5. IAlso,the sleeve valve'member 25 is provided, at approximately the same levelof portami, with a port l52 adapted tomove upwardly and downwardlyacross the transfer passage I8 .communicating with* the `companion powercylinder.

The sleeve valve member .25 of each `power cylinder, likewise, isprovided with a-wall port 54 adapted, with the reciprocal `action-'ofthe sleeve, to move upwardly and downwardly vacross`the transfer portI8, andwith a :port55 fata lower 4level that is adapted vto moveupwardly and gremains constant.

4 straight cut top and bottom edges so as to provide an instant cut oifor opening from one to the other when the ports move across each other.In Fig. `8 theirelationship and proportionate ver- .tical-dimensionspfthe ports I5, IBand 2U of the cylinder walls are shown, and thisrelationship Also, there is shown the relationship and proportionatevertical dimensions ofvports`il, 52,54 and 55 in the sleeve valvemembersand .the., location of these ports relative to the cylinder portsat the instant the port 50 of f" pumpsleeveizlstarts to move downwardlyinto registration with the fuel intake port I5.

' 4For better understanding of operation, it Will here be explained thatin the present instance the intakeport I-5'o'f cylinder Iii'hasavertical Ywidth of tical width of W8". The sleeve port 52 has a verticalwidth of 'f and its lower edge is level with the lower edge Vvof port50. The transfer passage I8 is Trin width vertically, and its bottomedge'is--- above the level of the bottom edge of the port |55. "TheAports5l and 55 in the sleeve '25 are each-M1 1in' vertical width andport 54 is positioned with its lower edge le above the level of thebottom edge of port 52, anclport55 is located with its top edge 1% belowthe bottom edge of port 54. vThe ports of the two sleeve valve membersmaintain a constant relationship to each other but change with respectto the cylinder ports with the reciprocal action of the sleeves as willbe understood by referencefto FigsfS to 7.

As a matter of explanation, it will further be mentioned'that in anengine using port dimensions as above notedgthe crank arms '40 and 31are each 21A" longrand the eccentric '4E is offset from the crank shaftaxis 1/2.

Assuming the Yparts Ito be so constructed and assembled', and the sparkplugs rconnected in a circuit thatis properly timed, operation of theunit of the engine is asA follows: Starting with the pistons intherelative positions shown in Fig. 3, and assuming the-crank shaft to berotatingclockwise, itiis understood by'reference to the position of thecrank armsthat the ltwo sleeve valve;members 25 and 26 and the pumppiston will be moving downwardly and the power piston will be movingupwardly. At the -instant the crank arm 4I] of the pump piston reaches aposition approximately 35.past top dead center, the lower edge oftheport 5l! of the sleeve'in the pump piston uncovers the top-edge ofthe intake port I5. Partial vacuum has already been createdin the pumpcylinder and as the pump piston rcontinues to move downand port50centinues-to uncoverinlet port I5, ycarbureted fuel is sucked .into:the vpump cylinder. With the rotation of the icrank shaft through anadditional @arc of the suction stroke Aof pump piston 33 will have been.finished andthe eccentric 46 will have moved the sleeves downwardly,causing port 5i! first to be registered with port I5land thenmovedupwardly out of registration, leaving. port I5 closed and :bringing theparts to vthe relative position of Fig. A4. YIn 'this position, the pumppiston is starting to'move upward, sleeve 2'6 has closed the intake portI5, and the previously intake fuel charge is'beginning to be compressedin the pump cylinder. The sleeves arebotlimoving upwardly andthe powerpiston is 'now moving downwardly.

As the partsmove from the position of Fig. 4 towardfand into theposition of Fig. 5,"the port 54 in sleeve 25 has moved upwardly'and hasLikewise, the'sleeve port 5B has a verslightly uncovered the transferport I8 as the top edge of port 52 comes even with the bottom edge ofthe transfer port. Thus, just prior to the opening of a passage for thedelivery of fuel charge from the pump cylinder to the power cylinder, asmall portion of burning fuel charge from the power cylinder will havecommunication through port 55 with the transfer passage I8, admittingburned gas thereinto. Then with the completing of the passage by theport 52 moving into registration with passage I8, the pressure ofburning fuel in the power cylinder will force some of this gas back intothe pump cylinder to mix with the fuel charge as a means of increasingits effectiveness; this use of gas from the explosion chamber havingbeen explained and its advantages described in my previous patents.

After the first initial blow of gas from the power cylinder into thepump cylinder, the increasing pressure in the pump cylinder reverses thedirection and as the rotation of the crank shaft advances the parts fromposition of Fig. 5 to that of Fig. 6, the upwardly moving pump pistonforces the fuel charge through the exchange passage i8, which isuncovered at this time by ports 52 and 55 of the upwardly movingsleeves. As the pump piston moves to its top limit of travel, as in Fig.'7, the power piston still moves upwardly on its compression stroke andsleeves, now moving downwardly, move the ports 52 and 54' below and outof registration with the exchange passage I8, thus to close off the pumpcylinder ,for the immediately following suction stroke of the pumppiston, and to close the power cylinder for the continued compression ofthe intaken charge by the upwardly moving power piston.

As the power piston continues to move upwardly, as from position of Fig.7 to top position, the charge is compressed and is ignited in propertiming to drive the piston on its down stroke. As the power piston movesdownwardly under force of expanding fuel, through positions of Figs. 4and 5, the two sleeves are being moved upwardly, finally bringing port55 in sleeve 25 into registration with the exhaust port 29 of the powercylinder, as the power piston 32 moves downwardly below the port 55,thus allowing the burned fuel charge to be exhausted. The exhaustion ofthe burned charge is forced by the incoming fresh charge which isadmitted during the final downward travel of the power piston, as inpassing from position of Fig. 5 to position of Fig. 6, by reason of thesleeve ports 52 and 54 being brought into registration with exchangepassage I8 as was previously explained.

As the fuel charge is being delivered to the power piston, the bailleextension of the power piston is opposite the port 54 as in Fig. 6, andthis operates to deflect the incoming charge to the top of the powercylinder, away from the exhaust port, and to force the burned fueldownwardly to the exhaust port.

The above described cycle as disclosed by the successive views of Figs.3 to 'l is repeated in rapid succession. Where more than one power unitis used, the crank shaft maintains the timed relationship of parts inthe units and between the units.

Having thus described my invention, what I claim as new therein anddesire to secure by Letters Patent is:

1. An engine of the character described comprising, in combination, apower cylinder and a pump cylinder having an exchange passage, a sleevereciprocally fitted in the pump cylinder, a pump piston reciprocallycontained in said sleeve, a sleeve reciprocally fitted in the powercylinder, a power piston reciprocally fitted in the second mentionedsleeve, a crank shaft to which said pistons are connected for equalreciprocal action with the pump piston substantially in advance of thepower piston, an eccentric on the crank shaft whereby said sleeves arereciprocated in unison through a relatively short travel interval; saidexchange passage being located approximately at the level of the upperlimit of travel olf the pump piston and near the lower level of travelof the power piston; said power cylinder having an exhaust portapproximately at the level of the lower limit of travel of the powerpiston; said pump cylinder having a fuel intake port spaced below thelevel of the exchange passage; said sleeve of the pump cylinder having aport that is moved downwardly into registration with the fuel intakeport for intaking fuel and then upwardly to close said port as the pumppiston moves through its suction stroke; and a second port therein thatis moved upwardly into registration with the exchange passage and thendownwardly to close the passage as the pump piston moves upwardly; saidsleeve of the power piston having a port therein that is moved upwardlyinto registration with the exchange passage but slightly in advance ofthe said second port of the other sleeve as the power piston movesupwardly, and a second port that is moved upwardly and into registrationwith the exhaust port of the power cylinder as the power piston moves toits lower limit of travel.

2. An engine of the character described comprising, in combination, apower cylinder and a pump cylinder having a connecting exchange passage,a sleeve valve reciprocally contained in said pump cylinder, a pistonreciprocally contained in the sleeve valve, a sleeve valve reciprocallyfitted in the power cylinder, a power piston reciprocally fitted in thesecond mentioned sleeve valve, a crank shaft to which said pistons areoperatively connected for equal reciprocal action with the pump pistonsubstantially in advance of the power piston, means on the crank shaftfor reciprocating the sleeve valves for admittance of fuel charges tothe pump cylinder and their delivery through the exchange passage to thepower cylinder, and the exhaustion of burned charges from the latter;said sleeve valves being operable to admit burning fuel through theexchange passage during a power stroke of the power piston, into thepump cylinder at the start of the delivery stroke of the piston therein.

OSCAR H. ERICKSON.

Howe et al. Apr. 22, 1919 Latta Apr. 28, 1925 FOREIGN PATENTS CountryDate Great Britain June 30, 1914 Number Number

